Identifier: morphologicalstu00camp (find matches)
Title: A morphological study of some members of the genus Pallavicinia
Year: 1914 (1910s)
Authors: Campbell, Douglas Houghton, 1859-1953 Williams, Florence
Subjects: Pallavicinia
Publisher: Stanford University, Cal., The University
Contributing Library: Smithsonian Institution Libraries
Digitizing Sponsor: Biodiversity Heritage Library

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nditions these giverise to normal branches. The archegonial plants of P. Levieri (Fig. 9, B), besides being muchlarger than the male plants, show also a very different appearance at theapex of the shoot. There is no indentation at this point, but the thallus isprolonged ino a nearly cylindrical process of some length, in which thewings are quite suppressed. It is possible that an examination of a largernumber of individuals might show that this difference in apices of themale and female plants is not constant. The rhizoids of the female plants 20 GENUS PALLAVICINIA of P. Levieri were much longer than those of either of the other specie?that were studied, sometimes reaching a length of a centimeter or moreThe archegonial receptacles are smaller than those of P. radiculosa, andare more like those of P. Zollingeri. The AntheridiumOf the three species examined, P. radiculosa was the best for thestudy of the young antheridium, as most of the stages of developmentwere found in the material.
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Fig. 10. Pallavicinia radiculosa. Early stages in the development of the antheridium.Longitudinal sections. D, F, are cut in a plane at right angles to E, G. METHODS 21 The young antheridium arises very near the apex of the thallus, as asingle large cell, projecting from the side of the midrib (Fig. 10, A).The first division wall is transverse, and separates a basal cell whichtakes no part in the development of the antheridium itself, and an outercell, which is the real mother-cell of the antheridium (Fig. 10, B). Atabout the same time that this transverse division is formed in the youngantheridium, certain neighboring superficial cells of the midrib becomeevident, which later form special structures accompanying the antheridia.Some of these companion cells secrete the mucilage which bathes theyoung antheridia; while others, not always readily distinguishable fromthe earliest stages of the antheridia themselves, finally develop into thecharacteristic scales covering the older antherid

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